The invention is in the field of semiconductor device manufacture, and relates more specifically to an improved method of making a silicon-on-insulator (SOI) material.
SOI materials are typically composed of a thin upper layer of silicon, in which semiconductor devices and integrated circuits are subsequently fabricated, an intermediate insulating layer, typically an oxide layer, and an underlying support layer or handler substrate, typically of silicon. Although various methods for fabricating the basic SOI material, which forms the starting point for integrated circuit manufacture, are known, the prior-art methods suffer from various drawbacks which limit their utility.
Accordingly, various techniques have been developed to permit the manufacture of SOI materials having superior properties. One such process, disclosed in U.S. Pat. No. 5,261,999, provides a method of producing SOI materials having superior properties and good thickness uniformity by using a technique known as "bond and etchback SOI" (BESOI). While this method is capable of producing high-quality SOI materials, the evolving requirements of manufacturing ever-smaller and more closely-packed integrated circuits make it desirable to achieve yet a further improvement in thickness uniformity in the SOI materials that are used as the starting point for integrated circuit manufacture.